Create the wiring for auto-commit confidence computation.

Bug: 9059617
Change-Id: I7e4e05ffa8c68cfebbe362a977fd176555cad12a
diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index c2aa8ba..c920f64 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -298,6 +298,9 @@
 #define NOT_AN_INDEX (-1)
 #define NOT_A_PROBABILITY (-1)
 #define NOT_A_DICT_POS (S_INT_MIN)
+// A special value to mean the first word confidence makes no sense in this case,
+// e.g. this is not a multi-word suggestion.
+#define NOT_A_FIRST_WORD_CONFIDENCE (S_INT_MIN)
 
 #define KEYCODE_SPACE ' '
 #define KEYCODE_SINGLE_QUOTE '\''